1. Field of the Invention
The present invention relates to a method for fabricating a molded resinous part with metal distributed in a surface thereof, more particularly, a method for fabricating an electroconductive molded resinous part with metal distributed in a surface thereof.
2. Description of Related Art
In the filed of electronic equipment with semiconductor elements mounted thereon, for the purpose of preventing mal-operation caused by electromagnetic waves and static electricity, resin-encapsulated semiconductor devices and resin-packaged or resin-housed electronic devices have been conventionally used. For such capsules, packages and housings, used are conductive resins made of resins kneaded with conductive powders, resinous parts molded in one piece with conductive coating, molded resinous parts provided with nonelectrolytic plating and the like.
However, in the case where a resin is kneaded with a conductive powder and a molded conductive resinous part is formed therefrom with use of a mold, a stable conductivity cannot be obtained because the conductive powder is dispersed in the resin, as shown in FIG. 3. Also, in order to attain a desired performance, a large amount of the conductive powder is requred. Consequently, the physical strength of the molded part is declined, the weight thereof is increased, and the production costs thereof is raised disadvantageously.
In the case where the molded resinous part is formed in one piece with the conductive film, the adhesion between the conductive film and the molded resinous part is not sufficient, and therefore, it is difficult to produce a molded resinous part having a stable conductivity.
In the case of nonelectrolytic plating is provided, a resin easy to plate is primarily molded, then a material hard to plate is injected into part of the molded product which part is not to be plated and the obtained product is secondarily formed. Or alternatively, part of the primarily molded product which part is to be plated is subjected to a surface activation treatment and then is nonelectrolytically plated. Thus the nonelectrolytic plating requires complicated processes, which increases production costs.